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A Z-scheme TiO2 quantum dots fragment-Bi12TiO20 composites for enhancing photocatalytic activity
摘要： To completely utilize the high redox ability of photo-induced charge carriers. Here, a Z-scheme photocatalyst of TiO2 QDs/Bi12TiO20 (TBT) composites with TiO2 QDs fragment attached to the surface of Bi12TiO20 (BTO) was prepared and the photocatalytic activity was evaluated by degradation of gatifloxacin (GF). The optimal photocatalytic performance of TBT displayed 3 times higher than bare BTO. The improved photocatalytic performance was ascribed to the effective separation of the charge carriers between TiO2 QDs and BTO via the direct Z-scheme heterojunction. Such a strategy for the construction of Z-scheme TBT composites for removal of organic pollutants, proving new insights into design photocatalyst.
关键词： Z-scheme,TiO2 quantum dots fragment,Mechanism,Bi12TiO20
更新于2025-09-16 10:30:52
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Direct Z-scheme photocatalytic removal of ammonia via the narrow band gap MoS2/N-doped graphene hybrid catalyst upon near-infrared irradiation
摘要： Near-infrared (NIR) irradiation accounts for approximately 54.3% of the solar spectrum. Therefore, MoS2 and N-doped graphene (NG) were utilised to fabricate a direct Z-scheme NIR-response photocatalytic system (MoS2/NG). The photocatalytic tests showed that MoS2/NG Z-scheme photocatalytic system can result in a 99.6% degradation ratio of ammonia under NIR irradiation, whereas the removal ratio of ammonia was only 64.0% using MoS2 as the photocatalyst under similar conditions. The catalytic e?ciency is still over 90.7% even if the MoS2/NG catalyst was used for ?ve runs, indicating that it is extremely stable. The kinetic research indicated the ?1. The average apparent rate constant kapp for ammonia degradation into N2 was at approximately 0.251 h enhanced photocatalytic activity of MoS2/NG was attributed to the more positive valence band level of the Z-scheme system.
关键词： MoS2/N-doped graphene,Near-infrared irradiation,Degradation ammonia,Narrow band gap,Z-scheme photocatalysis
更新于2025-09-12 10:27:22
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An improved scheme and numerical simulation of segmented planar imaging detector for electro-optical reconnaissance
摘要： Segmented planar photoelectric detection imaging technology is a cutting-edge photoelectric imaging technology developed to realize the miniaturization and weight reduction of imaging systems. The imaging process of the integrated optical interferometry system was simulated by a computer simulation algorithm, and the influence of the system’s structural parameters on the imaging results was explored. Moreover, an optimal scheme of the baseline matching method was proposed. The simulation results showed that increasing the number of interferometer arms and baselines can improve the imaging quality of the system. The proposed baseline matching optimization method could improve the low-frequency sampling rate of the system and thus, improve the imaging quality. In addition, simulation results also gave the optimal imaging distance of the system, which indicates that the system is most suitable for remote sensing imaging, meanwhile measuring the system’s tolerance limit to phase noise. The requirements for the precision of waveguide fabrication are given, which play a guiding role in system manufacturing.
关键词： Photoelectric detection,Numerical simulation,Photonic integrated circuit,Baseline optimization scheme,Interference imaging
更新于2025-09-12 10:27:22
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Combined implementation of smoothing technologies for improving illumination uniformity of laser quad in multi-directions
摘要： Azimuthal smoothing (AS) that enables the focal spot of a laser quad to rotate in a period of a few picoseconds can improve the illumination uniformity. However, the smoothing performance of azimuthal smoothing is worse than that of smoothing by spectral dispersion (SSD) due to the low rotation speed in the center area of the focal spot. A combined implementation of the schemes including smoothing by spectral dispersion, radial smoothing (RS) and azimuthal smoothing is discussed to achieve better and faster illumination uniformity. The theoretical models of the combined smoothing scheme have been built up to analyse the smoothing performance. The key parameters affecting the smoothing performance of the combined smoothing scheme are analysed and optimized, including the topological charge and the wavelength difference. The simulation results show that the illumination uniformity of the laser quad can be significantly improved in multi-directions by the combined smoothing scheme.
关键词： Inertial confinement fusion,azimuthal smoothing scheme,vortex beam,radial smoothing,uniformity,smoothing by spectral dispersion
更新于2025-09-12 10:27:22
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Second harmonic generation by circularly polarized laser beam propagating in obliquely magnetized plasma
摘要： An analytical study of intense radiation generation at second harmonic frequency, by a circularly polarized laser beam propagating in plasma, in presence of an obliquely applied magnetic field, has been presented. Considering a mildly relativistic regime, a perturbation scheme is used for evaluation of transverse components of current density. The current density oscillating at twice the fundamental frequency of the laser field, drives the second harmonic radiation. The amplitude of the circularly polarized second harmonic radiation is derived and its variation with obliqueness of the applied magnetic field is graphically depicted.
关键词： obliquely magnetized plasma,perturbation scheme,mildly relativistic regime,second harmonic generation,circularly polarized laser beam
更新于2025-09-12 10:27:22
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The spectroscopic properties of the low-lying excited states and laser cooling scheme of SrBr molecule
摘要： The potential energy curves and the transition dipole moments for seven electronic states of SrBr molecule are obtained via the multi-reference configuration interaction method and the all-electron basis sets. The Davidson and relativistic corrections are also included. Based on the obtained potential energy curves, the rotational and vibrational energy levels of each electronic state are determined by solving the nuclear motion equation of the molecule. The spectroscopic parameters are fitted from the obtained energy levels by using Dunham expression. Moreover, the spin-orbit coupling splits of the A2Π state are considered to construct the optical laser cooling scheme. The Frank-Condon factors, radiation lifetimes, radiation widths between the ground electronic state and 2Π1/2, 3/2/B2Σ+ states are calculated. Then, the feasibility of laser cooling is explored and the optical scheme is proposed. The results demonstrate that the SrBr molecule is a promising candidate for laser cooling.
关键词： Frank-Condon factors,optical scheme,laser cooling,Radiative lifetime,Spectroscopic parameter
更新于2025-09-12 10:27:22
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Parabolic two-step model and accurate numerical scheme for nanoscale heat conduction induced by ultrashort-pulsed laser heating
摘要： Simulation of nanoscale heat transfer phenomena has attracted great attention, particularly the nano-scale heat conduction induced by ultrashort-pulsed laser heating. In this article, we propose a nanoscale parabolic two-step model and an accurate numerical scheme for thermal analysis of the nanoscale heat conduction induced by ultrashort-pulsed laser heating. To this end, we first introduce the Knudsen number (Kn) into the original parabolic two-step heat conduction equations and couple them with the Kn-dependent and temperature-jump boundary condition. We then develop a fourth-order accurate compact finite difference method for solving the nanoscale model. Stability and convergence of the obtained numerical scheme are analyzed theoretically. We finally test the accuracy and applicability of the nanoscale model and the obtained numerical scheme in three examples. By choosing various values of the Kn and the parameter α in the boundary condition, the simulation could be a tool for analyzing the nanoscale heat conduction induced by ultrashort-pulsed laser heating.
关键词： Nanoscale heat conduction,Convergence,Compact finite difference scheme,Stability,Ultrashort-pulsed laser heating
更新于2025-09-12 10:27:22
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Black/red phosphorus quantum dots for photocatalytic water splitting: from a type I heterostructure to a Z-scheme system
摘要： By virtue of the quantum confinement effect, the junction between black phosphorus and red phosphorus changes from a type I heterostructure for bulk materials to a Z-scheme system for quantum dots. The Z-scheme system of black/red phosphorus quantum dots (BP/RP-QD) achieves H2 evolution from water splitting in the absence of sacrificial agents.
关键词： red phosphorus,black phosphorus,quantum dots,photocatalytic water splitting,Z-scheme system
更新于2025-09-12 10:27:22
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Facile constructing plasmonic Z-scheme Au NPs/g-C3N4/BiOBr for enhanced visible light photocatalytic activity
摘要： A novel ternary Au NPs/g-C3N4/BiOBr Z-scheme heterojunction composite was fabricated through hydrothermal and in-situ reduction method, and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet-visible diffuse reflection spectroscopy and photoluminescence emission spectroscopy. The photocatalytic activity was evaluated by the degradation of phenol under visible-light irradiation. It was found that Au NPs/g-C3N4/BiOBr showed enhanced photocatalytic activity, which is 3-fold higher than g-C3N4 and 2.5-fold higher than BiOBr. This could be attributed to the effective separation of photogenerated electron-hole pairs, narrowed band gap (2.10 eV) and surface plasmon resonance (SPR).
关键词： Au NPs/g-C3N4/BiOBr,Z-scheme,phenol,visible-light photocatlysis,plasmon
更新于2025-09-12 10:27:22
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Features of Operation of a Brightness Amplifier on Copper Bromide Vapors in the Bistatic Scheme of a Laser Monitor
摘要： The influence of the brightness amplifier operation mode on images formed with a bistatic laser monitor is studied. The bistatic laser monitor is an active optical system with two active elements. A possibility of imaging remote (to more than 5 m) objects with this instrument is evaluated. It is shown that a change in the concentration of active substance (copper bromide) of the amplifier significantly affects the amplification of the input signal. The active substance temperature rise from 480 to 550°C increases the gain throughout the input signal range. A further increase in the temperature (up to 570°C) increases the gain only at a relatively weak input signal (less than 100 mW). The resulting amplification characteristics of the active optical system are described and compared with the parameters of images formed (distortion and brightness).
关键词： remote objects,bistatic scheme of a laser monitor,brightness amplifiers,gain,active filtration,imaging,laser monitor
更新于2025-09-12 10:27:22